/* Block-relocating memory allocator.
- Copyright (C) 1993, 1995, 2000-2012 Free Software Foundation, Inc.
+ Copyright (C) 1993, 1995, 2000-2013 Free Software Foundation, Inc.
This file is part of GNU Emacs.
#ifdef emacs
#include <config.h>
-#include <setjmp.h>
+
#include "lisp.h" /* Needed for VALBITS. */
#include "blockinput.h"
#include <unistd.h>
-typedef POINTER_TYPE *POINTER;
-typedef size_t SIZE;
-
#ifdef DOUG_LEA_MALLOC
#define M_TOP_PAD -2
extern int mallopt (int, int);
#include <stddef.h>
-typedef size_t SIZE;
-typedef void *POINTER;
-
#include <unistd.h>
#include <malloc.h>
#include "getpagesize.h"
+typedef size_t SIZE;
+typedef void *POINTER;
#define NIL ((POINTER) 0)
/* A flag to indicate whether we have initialized ralloc yet. For
/* Declarations for working with the malloc, ralloc, and system breaks. */
/* Function to set the real break value. */
-POINTER (*real_morecore) (long int);
+POINTER (*real_morecore) (ptrdiff_t);
/* The break value, as seen by malloc. */
static POINTER virtual_break_value;
/* Macros for rounding. Note that rounding to any value is possible
by changing the definition of PAGE. */
#define PAGE (getpagesize ())
-#define ALIGNED(addr) (((unsigned long int) (addr) & (page_size - 1)) == 0)
-#define ROUNDUP(size) (((unsigned long int) (size) + page_size - 1) \
- & ~(page_size - 1))
-#define ROUND_TO_PAGE(addr) (addr & (~(page_size - 1)))
+#define ROUNDUP(size) (((size_t) (size) + page_size - 1) \
+ & ~((size_t)(page_size - 1)))
#define MEM_ALIGN sizeof (double)
-#define MEM_ROUNDUP(addr) (((unsigned long int)(addr) + MEM_ALIGN - 1) \
- & ~(MEM_ALIGN - 1))
+#define MEM_ROUNDUP(addr) (((size_t)(addr) + MEM_ALIGN - 1) \
+ & ~(MEM_ALIGN - 1))
/* The hook `malloc' uses for the function which gets more space
from the system. */
#ifndef SYSTEM_MALLOC
-extern POINTER (*__morecore) (long int);
+extern POINTER (*__morecore) (ptrdiff_t);
#endif
} *heap_ptr;
#define NIL_HEAP ((heap_ptr) 0)
-#define HEAP_PTR_SIZE (sizeof (struct heap))
/* This is the first heap object.
If we need additional heap objects, each one resides at the beginning of
}
if (! heap)
- abort ();
+ emacs_abort ();
/* If we can't fit SIZE bytes in that heap,
try successive later heaps. */
relinquish (void)
{
register heap_ptr h;
- long excess = 0;
+ ptrdiff_t excess = 0;
/* Add the amount of space beyond break_value
in all heaps which have extend beyond break_value at all. */
if ((char *)last_heap->end - (char *)last_heap->bloc_start <= excess)
{
- /* This heap should have no blocs in it. */
+ heap_ptr lh_prev;
+
+ /* This heap should have no blocs in it. If it does, we
+ cannot return it to the system. */
if (last_heap->first_bloc != NIL_BLOC
|| last_heap->last_bloc != NIL_BLOC)
- abort ();
+ return;
/* Return the last heap, with its header, to the system. */
excess = (char *)last_heap->end - (char *)last_heap->start;
- last_heap = last_heap->prev;
- last_heap->next = NIL_HEAP;
+ lh_prev = last_heap->prev;
+ /* If the system doesn't want that much memory back, leave
+ last_heap unaltered to reflect that. This can occur if
+ break_value is still within the original data segment. */
+ if ((*real_morecore) (- excess) != 0)
+ {
+ last_heap = lh_prev;
+ last_heap->next = NIL_HEAP;
+ }
}
else
{
excess = (char *) last_heap->end
- (char *) ROUNDUP ((char *)last_heap->end - excess);
- last_heap->end = (char *) last_heap->end - excess;
- }
-
- if ((*real_morecore) (- excess) == 0)
- {
- /* If the system didn't want that much memory back, adjust
- the end of the last heap to reflect that. This can occur
- if break_value is still within the original data segment. */
- last_heap->end = (char *) last_heap->end + excess;
- /* Make sure that the result of the adjustment is accurate.
- It should be, for the else clause above; the other case,
- which returns the entire last heap to the system, seems
- unlikely to trigger this mode of failure. */
- if (last_heap->end != (*real_morecore) (0))
- abort ();
+ /* If the system doesn't want that much memory back, leave
+ the end of the last heap unchanged to reflect that. This
+ can occur if break_value is still within the original
+ data segment. */
+ if ((*real_morecore) (- excess) != 0)
+ last_heap->end = (char *) last_heap->end - excess;
}
}
}
-
-/* Return the total size in use by relocating allocator,
- above where malloc gets space. */
-
-long
-r_alloc_size_in_use (void)
-{
- return (char *) break_value - (char *) virtual_break_value;
-}
\f
/* The meat - allocating, freeing, and relocating blocs. */
register bloc_ptr new_bloc;
register heap_ptr heap;
- if (! (new_bloc = (bloc_ptr) malloc (BLOC_PTR_SIZE))
+ if (! (new_bloc = malloc (BLOC_PTR_SIZE))
|| ! (new_bloc->data = obtain (break_value, size)))
{
free (new_bloc);
/* No need to ever call this if arena is frozen, bug somewhere! */
if (r_alloc_freeze_level)
- abort ();
+ emacs_abort ();
while (b)
{
/* No need to ever call this if arena is frozen, bug somewhere! */
if (r_alloc_freeze_level)
- abort ();
+ emacs_abort ();
if (bloc == NIL_BLOC || size == bloc->size)
return 1;
}
if (heap == NIL_HEAP)
- abort ();
+ emacs_abort ();
old_size = bloc->size;
bloc->size = size;
}
else
{
- memmove (b->new_data, b->data, b->size);
+ if (b->new_data != b->data)
+ memmove (b->new_data, b->data, b->size);
*b->variable = b->data = b->new_data;
}
}
}
else
{
- memmove (bloc->new_data, bloc->data, old_size);
+ if (bloc->new_data != bloc->data)
+ memmove (bloc->new_data, bloc->data, old_size);
memset ((char *) bloc->new_data + old_size, 0, size - old_size);
*bloc->variable = bloc->data = bloc->new_data;
}
}
else
{
- memmove (b->new_data, b->data, b->size);
+ if (b->new_data != b->data)
+ memmove (b->new_data, b->data, b->size);
*b->variable = b->data = b->new_data;
}
}
free_bloc (bloc_ptr bloc)
{
heap_ptr heap = bloc->heap;
+ heap_ptr h;
if (r_alloc_freeze_level)
{
bloc->prev->next = bloc->next;
}
- /* Update the records of which blocs are in HEAP. */
- if (heap->first_bloc == bloc)
- {
- if (bloc->next != 0 && bloc->next->heap == heap)
- heap->first_bloc = bloc->next;
- else
- heap->first_bloc = heap->last_bloc = NIL_BLOC;
- }
- if (heap->last_bloc == bloc)
+ /* Sometimes, 'heap' obtained from bloc->heap above is not really a
+ 'heap' structure. It can even be beyond the current break point,
+ which will cause crashes when we dereference it below (see
+ bug#12242). Evidently, the reason is bloc allocations done while
+ use_relocatable_buffers was non-positive, because additional
+ memory we get then is not recorded in the heaps we manage. If
+ bloc->heap records such a "heap", we cannot (and don't need to)
+ update its records. So we validate the 'heap' value by making
+ sure it is one of the heaps we manage via the heaps linked list,
+ and don't touch a 'heap' that isn't found there. This avoids
+ accessing memory we know nothing about. */
+ for (h = first_heap; h != NIL_HEAP; h = h->next)
+ if (heap == h)
+ break;
+
+ if (h)
{
- if (bloc->prev != 0 && bloc->prev->heap == heap)
- heap->last_bloc = bloc->prev;
- else
- heap->first_bloc = heap->last_bloc = NIL_BLOC;
+ /* Update the records of which blocs are in HEAP. */
+ if (heap->first_bloc == bloc)
+ {
+ if (bloc->next != 0 && bloc->next->heap == heap)
+ heap->first_bloc = bloc->next;
+ else
+ heap->first_bloc = heap->last_bloc = NIL_BLOC;
+ }
+ if (heap->last_bloc == bloc)
+ {
+ if (bloc->prev != 0 && bloc->prev->heap == heap)
+ heap->last_bloc = bloc->prev;
+ else
+ heap->first_bloc = heap->last_bloc = NIL_BLOC;
+ }
}
relinquish ();
__morecore hook values - in particular, __default_morecore in the
GNU malloc package. */
-POINTER
-r_alloc_sbrk (long int size)
+static POINTER
+r_alloc_sbrk (ptrdiff_t size)
{
register bloc_ptr b;
POINTER address;
if (! r_alloc_initialized)
r_alloc_init ();
- if (! use_relocatable_buffers)
+ if (use_relocatable_buffers <= 0)
return (*real_morecore) (size);
if (size == 0)
header. */
for (b = last_bloc; b != NIL_BLOC; b = b->prev)
{
- memmove (b->new_data, b->data, b->size);
+ if (b->new_data != b->data)
+ memmove (b->new_data, b->data, b->size);
*b->variable = b->data = b->new_data;
}
for (b = first_bloc; b != NIL_BLOC; b = b->next)
{
- memmove (b->new_data, b->data, b->size);
+ if (b->new_data != b->data)
+ memmove (b->new_data, b->data, b->size);
*b->variable = b->data = b->new_data;
}
}
dead_bloc = find_bloc (ptr);
if (dead_bloc == NIL_BLOC)
- abort (); /* Double free? PTR not originally used to allocate? */
+ emacs_abort (); /* Double free? PTR not originally used to allocate? */
free_bloc (dead_bloc);
*ptr = 0;
bloc = find_bloc (ptr);
if (bloc == NIL_BLOC)
- abort (); /* Already freed? PTR not originally used to allocate? */
+ emacs_abort (); /* Already freed? PTR not originally used to allocate? */
if (size < bloc->size)
{
return *ptr;
}
-/* Disable relocations, after making room for at least SIZE bytes
- of non-relocatable heap if possible. The relocatable blocs are
- guaranteed to hold still until thawed, even if this means that
- malloc must return a null pointer. */
-
-void
-r_alloc_freeze (long int size)
-{
- if (! r_alloc_initialized)
- r_alloc_init ();
-
- /* If already frozen, we can't make any more room, so don't try. */
- if (r_alloc_freeze_level > 0)
- size = 0;
- /* If we can't get the amount requested, half is better than nothing. */
- while (size > 0 && r_alloc_sbrk (size) == 0)
- size /= 2;
- ++r_alloc_freeze_level;
- if (size > 0)
- r_alloc_sbrk (-size);
-}
-
-void
-r_alloc_thaw (void)
-{
-
- if (! r_alloc_initialized)
- r_alloc_init ();
-
- if (--r_alloc_freeze_level < 0)
- abort ();
-
- /* This frees all unused blocs. It is not too inefficient, as the resize
- and memcpy is done only once. Afterwards, all unreferenced blocs are
- already shrunk to zero size. */
- if (!r_alloc_freeze_level)
- {
- bloc_ptr *b = &first_bloc;
- while (*b)
- if (!(*b)->variable)
- free_bloc (*b);
- else
- b = &(*b)->next;
- }
-}
-
#if defined (emacs) && defined (DOUG_LEA_MALLOC)
}
if (bloc == NIL_BLOC || bloc->variable != old)
- abort (); /* Already freed? OLD not originally used to allocate? */
+ emacs_abort (); /* Already freed? OLD not originally used to allocate? */
/* Update variable to point to the new location. */
bloc->variable = new;
}
+void
+r_alloc_inhibit_buffer_relocation (int inhibit)
+{
+ if (use_relocatable_buffers > 1)
+ use_relocatable_buffers = 1;
+ if (inhibit)
+ use_relocatable_buffers--;
+ else if (use_relocatable_buffers < 1)
+ use_relocatable_buffers++;
+}
+
\f
/***********************************************************************
Initialization
first_heap->start = first_heap->bloc_start
= virtual_break_value = break_value = (*real_morecore) (0);
if (break_value == NIL)
- abort ();
+ emacs_abort ();
extra_bytes = ROUNDUP (50000);
#endif
#ifdef DOUG_LEA_MALLOC
- BLOCK_INPUT;
+ block_input ();
mallopt (M_TOP_PAD, 64 * 4096);
- UNBLOCK_INPUT;
+ unblock_input ();
#else
#ifndef SYSTEM_MALLOC
- /* Give GNU malloc's morecore some hysteresis
- so that we move all the relocatable blocks much less often. */
- __malloc_extra_blocks = 64;
+ /* Give GNU malloc's morecore some hysteresis so that we move all
+ the relocatable blocks much less often. The number used to be
+ 64, but alloc.c would override that with 32 in code that was
+ removed when SYNC_INPUT became the only input handling mode.
+ That code was conditioned on !DOUG_LEA_MALLOC, so the call to
+ mallopt above is left unchanged. (Actually, I think there's no
+ system nowadays that uses DOUG_LEA_MALLOC and also uses
+ REL_ALLOC.) */
+ __malloc_extra_blocks = 32;
#endif
#endif